Universal joint marine master bushing



Nov. 12, 1963 w, sPlRl 3,110,350

UNIVERSAL JOINT MARINE MASTER BUSHING s Sheets-Sheet 1 Filed Jan. 11, 1957 1 24 17 10. 5. J ll IG- j' 7 10a 65 3! Z? 55 5 LI "ALE"? is re 7 Z/IZAIf/ZM xirrvpugg.

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Nov. 12, 1963 w. H. SPIRI UNIVERSAL JOINT MARINE MASTER BUSHING 3 Sheets-Sheet 2 Filed Jan. 11, 1957 w. H. SPIRI 10,350;

UNIVERSAL JOINT MARINE MASTER BUSHING 3 Sheets-Sheet 3 Nov. 12, 1963 Filed Jan. 11, 1957 7? W/1.1.y J1: p/el,

f/wsu r02 United States Patent This invention relates to improved apparatus for drilling wells beneath water and particularly to improved master bushing assemblies for use in the rotary table of a marine well drilling rig.

In recent years, there has been increased interest in the drilling of oil wells beneath oceans, lakes and other bodies of water. Such marine drilling is peiformed by mounting the drilling rig, including the derrick, rotary table and other apparatus, on a barge or ship which is anchored over the desired drilling location, so that the drill string may extend downwardly from the barge through the water and then into the earth formation beneath the water.

One difficulty that has been encountered in this marine drilling has been the fact that the barge does not at all times remain in fixed exactly horizontal position, but instead often rocks in accordance with movements of the water, with the result that the rotary table and other equipment also move with the water and thus tend to bend the drill string back and forth in the water as the rig moves. This of course, is extremely harmful to all of the equipment involved, and decreases the eflectiveness with which the drilling operation may be controlled.

The general object of the present invention is to provide an improved master bushing assembly for such a marine rig, to be positioned in the rotary table about the drill pipe or other well pipe, and which is so designed as to allow the orientation of the pipe at the table location and relative to the rotary table to change in response to movements of the table with the supporting water, to thus materially reduce the bending of the pipe which must occur, and also to'reduce the damage encountered heretofore by virtue of the inability of the pipe to thus adjust its position relative to the rotary table. For this purpose, I so form the bushing assembly as to include a universal joint or connection acting to allow universal movement of a portion of the assembly relative to the rotary table, so that such universal movement will allow for the specified adjusting movement of the pipe relative to the table. More specifically, the bushing assembly may include an inner part which supports or drives the pipe in fixed orientation with respect thereto, and an outer part which is fixed relative to and driven by the rotating portion of the rotary table, with a universal connection being provided between these parts.

The universal connection may include an intermediate pm which is connected to the inner and outer parts respectively for a relative pivotal movement about two perpendicular horizontal axes. To assist in supporting the tremendous weight of the well pipe, there may be provided an additional bearing structure, preferably consisting of a series of ball bearings engaging spherically curved bearing surfaces on one or both of the inner and outer parts.

The inner bushing part is adapted to receive and rotatively drive a Kelly bushing, for turning the drill string. Also, the inner bushing part is adapted to receive and support a number of slips for supporting a Well pipe from the assembly. The support of the well pipe may be effected through a slip bowl structure which is removably received within the inner bushing part.

3,11%,350 Patented Nov. 12, 1963 The above and other features of the present invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawings in which:

FIG. 1 is a view representing a marine drilling'rig utilizing a master bushing assembly constructed in accordance with the invention;

FIG. 2 is an enlarged view of the FIG. 1 master bushing assembly, with a Kelly bushing positioned within the master bushing structure;

FIG. 3 is a further enlarged partially sectional view of the device shown in FIG. 2, and taken on line 33'of FIG. 4;

FIG. 4 is a fragmentary plan view of the FIG. 3 apparatus, taken on line 44 of FIG. 3;

FIG. 5 is a fragmentary vertical section taken on line 55 of FIG. 4;

FIG. 6 is a fragmentary horizontal section taken on line 66 of FIG. 3;

FIG. 7 is a horizontal section taken on line 77 of FIG. 2;

FIGS. 8 and 9 are fragmentary horizontal sections taken on line 8-8 of FIG. 3, and showing the actuating handle for the slip bowl retaining lock element in its elevated and lowered positions respectively;

FIG. lO-is an exploded perspective view representing the master bushing assembly and the Kelly bushing in relatively separated positions;

FIG. 11 is a vertical section through the bushing assembly, but showing slips positioned in that assembly, rather than a Kelly bushing; and e 7 FIG. 12 is a perspective view of one of the seal gaskets of the apparatus. 7

Referring first to FIG. 1, I have shown at 10 a barge or boat which is designed for drilling a well 11 within the earth formation 12 beneath an ocean or other body of water 13 on which the barge 10 is supported. This barge is retained in any suitable manner at a substantially fixed location over the well location 11, as by means of a number of anchors resting on the floor of the body of water and connected to the boat by chains represented at 14. The barge is, however, free for rocking or tilting" tion. This Kelly section 17 passes through a conventional rotary table 18 mounted on the barge, and is supported and advanced vertically by means of the usual apparatus associated with upstanding derrick 191. The rotary table 18 is of conventional construction, including an outer rigid section 19 which is mounted in fixed position relative to the body of barge 10, and an inner section 20 which is supported by suitable bearings for rotation about a normally vertical axis 21 relative to stationary section 19; This inner rotating section 20 is essentially annular, and is rotatably driven by a power operated engine 22.

With reference now to FIGS. 2 and 3, the rotary inner section 20 of the rotary table contains a vertically extending opening 23 centered about axis 21 and within which a master bushing assembly 24- is supported. This master brushing assembly is adapted to receive and support, as well as rotatively drive, a Kelly bushingZS, for transmitting rotation to kelly 17. Opening .23 in the rotary portion 20 of the rotary table has an upper portion 2a of non-circular and preferably square horizontal section, beneath which the rotary table opening 23 may have a portion 27 of circular horizontal section and of a smaller horizontal dimension than upper portion 26. The bearings for rotatively supporting inner section 26 of the robushing 26.

tary table within outer section 19 are typically represented at 28 in FIG. 2.

The master bushing assembly 24 includes a first generally annular outer body section 2.9 within which there is mounted for universal tilting movement an essentially annular inner body section 36. The universal mounting of inner section 30 is efiected in part by means or" an intermediate annular section 31 of the master bushing assembly. Outer section 29 of the master bushing assembly has an upper annular portion 32 which projects laterally overthe inner edge portion of part 24} of the rotary table, to engage the rotary table at 33 and be supported thereby. Beneath this upper annular portion 32, the outer section 29 of the master bushing assembly has a vertically intermediate reduced diameter externally non-circular portion 34 which is received within the upper non-circular portion 26 of the rotary table opening 23, and is rotatively driven thereby about axis 21. Preferably, the bushing portion 34 is of essentially square horizontal section, dimensioned in accordance with the correspondingly square portion 26 of the rotary table opening, but typically having the four corners of portion 34 cut off angularly at 340. Beneath portion 34, bushing section 29 has a portion adapted to be received within the circular lower portion 27 of the rotary table opening, and having a circular surface 35 engaging and centered within the wall of that opening. Between intermediate portion 34 and the lower part of ele- 'ment 29, this element has a horizontal shoulder 36 which engages a corresponding horizontal shoulderin the rotary table part 20, to assist shoulders 33in supporting the bushing structure within the rotary table.

The inner section 30 of the master bushing structure contains an opening 37 extending vertically therethrough and centered'about axis 21, and through which the kelly and drill pipe may extend vertically. This opening 37 within part 30 has an upper portion 38 of non-circular horizontal section, and has two cylindrical portions 3-9 and 40 beneath upper portion 38. The lower of these cylindrical portions may be of a diameter slightly smaller than portion 39, with an annular essentially horizontal shoulder 41 being provided between cylindrical surfaces 39 and 40, so that a pair of complementary semi-circular slip bowl segments 42 may be received within the lower portions 39 and 40 of the opening 37. These slip bowl segments have outer cylindrical surfaces :3 and 44 engaging and horizontally backed upby surfaces 39 and 40, with essentially horizontal shoulders 45 being provided on the slip bowl segments to engage and be supported by shoulder 41 on part 30. Internally, the two slip bowl segments form together an opening 46 of upwardly flaring frusto-conical configuration, for receiving and supporting a number of pipe supporting slips 47 (see FIG. 11).

The Kelly bushing 26 may typically be of the type described and claimed in Patent No. 2,346,958 issued to W. A. Abegg on April 18, 1944, and entitled Kelly Bushing! Specifically, this kelly bushing may include a rigid body section 48 containing an opening 49 through which the kelly 17 extends vertically, with four rollers 50 being rotatively mounted by transverse pins 51 for rotation relative to body 48 at locations spaced uniformly about kelly 17. Referring to FIG. 7, these rollers have peripheral grooves 52 on V-shaped cross section, adapted to receive the four corners respectively of the square kelly .17, to rotatively drive the kelly while allowing relative vertical movement of the kelly by virtue of the rotation of rollers 50. The body 43 or Kelly bushing 26 projects upwardly above the master bushing assembly 24, and extends downwardly within the bushing assembly in a relation transmitting rotation from assembly 24 to Kelly More specifically, the body 48 of the Kelly bushing has a portion 53 of non-circular and preferably square external horizontal section, typically having its corners bevelled at 53a, which portion is received within portion 38 of bushing opening 37 to be rotatively driven thereby. Beneath square portion 53, body 48 of the Kelley bushing has a lower essentially circular and re duced dimension portion 54- received within and centered by the slip bowl segments 42.

The upper non-circular portion 33 of opening 37 in part 3t) may be considered as being essentially square, having its four corners definedat 55, but perhaps with small angular fillet portions 56 at the'exact corners of this portion or" the opening. Intermediate these four corners 55, the sidewalls 57 of the upper non-circular portion 38 of opening 37 may have portions 58 which extend arcuately outwardly beyond the vertical plane of the rest 7 of the straight sided portions of wall 57, with these four portions 58 being upper continuations of the cylindrical surface 39, whose diameter is somewhat greater than the narrowest width of the square defined by corners 55. As will be understood, the square portion 53 of the Kelly bushing is of a size corresponding to the square defined by corners 55 of opening 37, so that the corners of the Kelly bushing portion fit within corners 55 and are rotatably driven thereby. The Kelly bushing is supported within the opening 37 by en agement of horizontal shoulders 59 as the underside of the square portion 53 of the Kelly bushing with corresponding upper horizontal surfaces on either the part 3% (within corners 55) or the slip bowl segments 42.

These slip bowl segments are adapted to be releasably locked in their illustrated positions within part 30 by means or" a pair of horizontally slidable lock elements 6% movably carried by part 36 at a pair of-diametrically opposite locations. These lock elements 64} are confined within a pair of horizontal guide recesses 61 in part 3%) for sliding movement between released positions of reception completely within those recesses 61, and active positions (see PEG. 3) in which the inner portions or element 653 are received over the end of slip bowl seg ments 42. Each of these lock elements 6% is actuable between the two defined positions by means of a vertically extending actuating pin 62, which is mounted within a cylindrical vertical bore 63 for rotation about an axis parallel to axis 21. To allow such rotation, the pins 62. have external cylindrical surfaces 64 of a diameter corresponding to and engaging the inner wall of bore 63, and allowing limited vertical movement of part 62 within bore 63. The lower end of each pin 62 has an eccentric cylindrical portion 65, which passes through an opening 66 in the associated part 66, to actuate that part 60 between its two active and retracted positions in accordance with the rotation of part 62 about its vertical axis.

At its upper end, each pin 62 carries a transverse handle element 67, which is utilized for turning pin 62 about its axis. In the PIG. 3 lowered position of element 62, the handle 67 is received-within a horizontal groove 68 formed in the upper surface of part 39, and confining handle 67 in a manner preventing rotation of pin 62 from whichever position it happens to be in. In this way, element 60 can be retained ineither its active or retracted position. To actuate element 60 between these two positions, handle 67 is lifted out of recess 68, and then turned through 18Q and allowed to fall back into the recess with part 60* in the changing position. For assisting handle 67 and groove 68 in assuring retention of part 6% in either of its two positions, the body 30 may carry a horizontal pin 69, which is engageable with a pair of flats 76 and 71 on pin 62 in the active and retracted positions respectively of element 69 (see FIG. 9), so that when. pin 69 engages either of these flats, element 62. is retained against rotation about its vertical axis. When, however, element 62 is raised to a position in which handle 67 is no longer received within groove 68, then pin 69 is received within an annular groove in part 62 to allow free rotation of part 62 within its bore 63. The two locl-r elements 61), when in their active locking positions of FIG. 3, are received laterally outwardly of the square portion 53 of kelly bushing 26, so that these elements 60 and slip bowl segments 42 do not interfere with positioning of the kelly bushing within the master bushing assembly.

To now describe the manner in which inner section 39 of the master bushing assembly is mounted for universal tilting movement with respect to outer section 29 of the master bushing assembly, it is first of all noted that the upper portions of elements 29 and 3-0 are spaced radially apart, and have intermediate element 31 received therebetween. This element 31 is annular except as interrupted to provide for engagement with four circularly spaced pivot pins 73, 74, '75 and 76, and the internal surfaces of part 29 and the external surfaces of part 30 are also annular except as interrupted at the locations or" pins 73, 74, 7'5 and 76. The two pivot pins 73 and 75 are positioned at diametrically opposite locations, and in axial alinement one with the other, to interconnect parts 29 and 31 for relative pivotal movement about a horizontal axis 77 extending through the vertical axis 21 of the apparatus. These two Pivot pins 73 and 75 are externally cylindrical and have inner portions 78 rotatably journalled within sleeve bushings 79 contained within bores 80 in part 31. At their radially outer ends, pins 73 have enlarged flanges 81, which are attached by screws 82 to part 29, flanges 81 being preferably received within outer circular recesses 132 in part 29.

Pins 74 and 76 form pivotal connections between parts 39 and 31, interconnecting these parts for relative pivotal movement about an axis 83 extending perpendicularly to axis 77 and intersecting that axis and axis 21 at a common point. These pins 74 are externally cylindrical, having outer ends received Within bushings 84 and bores 85 within part 31, and having inner enlarged flange portions 86 received within recesses 87 in part 3i} and attached to part 39 by screws 88. Thus, the two sets of pins 73-45 and 7476 fonm together a universal mounting for inner part 30.

In order to assist the pins 73, 74, '75 and 76 in mounting inner section 3% for universal movement, there is provided beneath these pins and between parts 29 and 30 a second universal connect-ion, consisting of a ball bearing assembly 89 (see FIG. 3) engaging a pair of hardened metal bearing rings 94} and $1 mounted within recesses 92 and 93' in parts 2 and 3% respectively. The ball bearing assembly $59 includes an annular series of balls 93 rotatively carried by a retainer ring 94, with the series of ball bearings being centered about the axis 21 of the apparatus. The surfaces 95 and 96 of parts 90 and 91 respectively, which surfaces are engaged by balls 93, are both spherically curved about the point 97 at which the two previously mentioned axes 77 and 83 intersect, so that the engagement of balls 93 with surfaces 95 and 96 form a universal connection supporting part 36 for universal movement about the same center as that associated with the pivoting pins 7376. If desired, a number of screws 98 and 99 may be mounted in parts 29 and 3t respectively at circularly spaced locations, to be tightenable against rings 99 and 91 for adjusting them vertically a small distance relative to parts 29 and 39, to thus properly adjust the ball bearing mechanism so that its center will be properly located with respect to the pivot pins.

The universal movement of part 39 relative to part 29 is limited by engagement of ring 94 of the ball bearing assembly with annular shoulders 11% formed on parts 29 and 30 at the radially inner and outer extremities of surfaces 95 and 96 and the continuations thereof formed by parts 29 and 39.

Preferably, the entire space between parts 29 and 3d and around the vicinity of ball bearing assembly 89 is filled with a suitable grease, to effectively lubricate the bearing arrangement. In order to prevent the access of water or other fluid downwardly to this grease containing space, I provide between pants 29 and 31 a seal ring 101,

and between parts 30 and 31 a similar seal ring 1432.

Referring to FIG. 12, each of these rings is formed of an essentially annular piece of deformable seal material, such as rubber, which is shaped to have a pair of diametrically opposite circular portions 103 to extend about and form a fluid seal about the associated pins 73 and 75 or '74 and 76. Also, each of these rings is confined within an annular recess or groove formed in part 29 or 31, and engages a pherically curved surface on the other associated part (surface 154 on part 31 or surface 105 on part 30), to form an annular fluid tight seal between the engaged parts regardless of the position to which par-ts 3G or 31 may 'be tilted relative to outer part 29.

To now describe the operation of the illustrated apparatus, assume first that it is desired to utilize the apparatus for rotatively driving a kelly 17 and associated drill string 15. In this case, the kelly bushing 26 is inserted within the master bushing assembly to the position of FIG. 2, and the kelly 17 extends vertically through the kelly bushing. When engine 22 is then started, to rotatively drive section 23 of the rotary table about axis 21, this rotation of the table turns the entire master bushing assembly 24 and kelly bushing 26, to thus turn the kelly and the drill string, for drilling the well =11. If barge 10 moves to a tilted position, say to the position of FIG. 1, then the inner section 30 of the master bushing is free to swing about center 97 and with the kelly bushing to a tilted position, to thus partially compensate for the tilting of the barge and the rest of the apparatus, and avoid the intro-.

sally movable part 30 may move in correspondence with movements of the barge. Pins 73-76, though efiective to transmit rotary movement from part 32 to part 30, allow very free relative universal movement of part 30, since pins 73 and 75 mount ring 31 to ring 32 for pivotal movement about axis 77, and pins 74 and 76 mount ring 30 for pivotal movement relative to ring 31 about axis 83. If it is later desired to remove the kelly, and utilize the master bushing for supporting a drill pipe from the rotary table, then the kelly bushing 25 may be removed, and -a number of slips 47 may be inserted into the slip bowl segments 42 (see FIG. 11), to support the pipe by means of the slips. The s1ips47, of course, have outer downwardly converging conical surfaces 111 which engage and are wedged inwardly by the inner surfaces 46 to be drawn through the master bushing assembly.

I claim:

l. A bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section having a spherically curved bearing surface and adapted to be received in said opening and be rotatably driven by the rotary table about an essentialy vertical axis, a sec end section supported and driven by said first section and having a spherically curved bearing surface and adapted to rotatively drive a kelly, and a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn, said universal connection including a third section turning with said first and second sections, a first pivotal connection between said first and third sections for driving the latter with the former while allowing relative tilting movement of said third section about a first essentially horizontal axis, a second pivotal connection tions in supporting the drill pipe weight while allowing said universal movement.

2. A bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including an inner bushing part adapted to extend about the pipe and to drive a kelly for rotating the pipe, a second part disposed about and driving said bushing part, an outer part disposed about and driving said second part and having an externally noncircular portion adapted to be received in a correspondingly non-circular portion of said opening in the rotary table to thereby be driven by the table, a connection mounting said second part into said outer part for pivotal movement relative thereto about an essentially horizontal axis, a second connection mounting said inner part in said second part for pivotal movement relative thereto about a second essentially horizontal axis extending transversely of the first axis, whereby said two pivotal connections and said second part form together a universal drive joint between said outer and inner parts, said outer and inner parts having opposed spherically curved bearing surfaces, and there being an annular series of ball bearings between and engaging said spherically curved surfaces at a location lower than said two axes to assist in supporting the drill pipe weight during universal movement of the inner part relative to the outer part.

3. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting drive means on the table to rotatably drive said first section with the table, arsecond section supported and driven by said first section and adapted to removably recive a kelly bushing, drive means on said second section for interfitting with said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table'and sections turn,-said universal connection includ ing two hinge connections mounting said second section to swing about two intersecting essentially horizontal axes respectively relative to said first section and transmitting rotary motion between said sections, and additional hearing means for supporting said second section from the first section and including means engaging an arcuately curved surface on one of the sections at a location offset vertically from the plane of said axes and ma relation sup porting said second section while allowing said universal movement thereof. 1

4. A bushing assembly as recited in claim 2, in which each of said inner and outer parts includes a main body portion, a ring adjustably mounted thereto and having one of said spherically curved bearing surfaces formed thereon, and means for adjusting said ring relative to said main .body portion of the part.

5. A bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including an inner bushing part adapted to extend about the pipe and to drive a kelly for rotating the pipe, a second part disposed about and driving said bushing part, an outer part disposed about and driving said second part and having rasso an externally non-circular portion adapted to be received connection mounting said second part into said outer part for pivotal movement relative thereto about an essentially horizontal axis, a second connection mounting said inner part in said second part for pivotal movement relative thereto about a second essentially horizontal axis extending transversely of the first axis, whereby said two pivotal connections and said second part form together a universal drive joint between said outer and inner parts, said outer and inner parts having opposed spherically curved bearing surfaces, and there being an annular series of ball bearings between and engaging said spherically curved surfaces to assist in supporting the drill pipe weight during universal movement of the inner part relative to the outer part,.said two pivotal connections comprising two pairs of hinge pins connecting said parts for said pivotal movements with the two pins of each pair in axial alinement and at opposite sides of said inner parts and with one pair of pins being offset with respect to the other, said spherically curved surfaces and ball bearings being located beneath said pins and beneath said second part in the assembly.

6. A bushing assembly as recited in claim 5, including two essentially annular seal elements one interposed between and engaging said outer and second parts and the other interposed between and engaging said second and inner parts above said ball bearings and said spherically curved surfaces.

7. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting drive means on the table to rotatably drive said first section with the table, a second section supported and driven by said first section and adapted to removably receive a kelly bushing, drive means on said second section for interfitting with said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn and transmitting rotary motion between said sections, said universal connection including a third section, a first hinge connection mounting said third section to said first section for relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotal movement about a second essentially horizontal axis which intersects said first horizontal axis, and additional bearing means for supporting said second section from the first section and including a spherically curved surface on one of said first and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movably engaging said spherically curved surface at a location offset vertically from the plane of said horizontal axes and at points on a sphere to support said second section while allowing said universal movement thereof, said surface being curved spherically about essentially the point of intersection of said two axes of said hinge connections;

8. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting drive means on the table to rotatably drive said first section with the table,

a second sectionsupported and driven by saidfirst section and adapted to removably receive a kelly bushing, drive means on said section section for interfitting with said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal mmement relative to the first section as the table and sections turn and transmitting rotary motion beween said sections, said universal connection including a third section, a first hinge connection mounting said third section to said first section for relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotal movement about a second essentially horizontal axis which intersects said first horizontal axis, and additional bearing means for supporting said second section from the first section and including a spherically curved surface on one of said fii-rst and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movably engaging said spherically curved surface at a location ofiset vertically from the plane of said horizontal axes and at points on a sphere to support said second section while allowing said universal movement thereof, said second section having a pipe passing opening extending vertically therethrough, and slip bowl means removably receivable in said opening in the second section and having an upwardly flaring inner surface adapted to receive and support pipe engaging slips.

9. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting drive means on the table to rotatably drive said first section with the table, a second section supported and driven by said first section and adapted to removably receive a kelly bushing, drive means on said section section for interfitting with said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn and transmitting rotary motion beween said sections, said universal connection including a third section, a first hinge connection mounting said third section to said first section for relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotal movement about a second essentially horizontal axis which intersects said first horizontal axis, and additional bearing means for supporting said second section from the first section and including a spherically curved surface on one of said first and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movably engag'ng said spherically curved surface at a location offset vertically from the plane of said horizontal axes and at points on a sphere to support said second section while allowing said universal movement thereof, said second section having a pipe passing opening extending vertically therethrough having a lower circular portion and an upper non-circular portion adapted to receive and drive a kelly bushing, and a plurality of slip bowl segments removably supported in said lower circular portion of said opening.

10. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting drive means on the table to rotatably drive said first section with the table, a second section supported and driven by said first section and adapted to removably receive a kelly bushing, drive means on said section section for interfitting with said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn and transmitting rotary motion beween said sections, said universal connection including a third section, a first hinge connection mounting said third section to said first section for relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotal movement about a second essentially horizontal axis which intersects said first horizontal axis, and additional bearing means for sup porting said second section from the first section and including (a spherically curved surface on one of said first and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movably engaging said spherically curved surface at a location oifset vertically from the plane of said horizontal axes and at points on a sphere to support said second section while allowing said universal movement thereof, and a kelly bushing supported and rotatably driven by said second section.

11. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting' drive means on the table to rotatably drive said first section with the table, a second section supported and driven by said first section and adapted to removably receive a kelly bushing, drive means on said second section for interfitting with said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn and transmitting rotary motion beween said sections, said universal connection including a third section, a first hinge connection mountingtsaid third section to said first section for relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotal movement about a sec ond essentially horizontal axis which intersects said first horizontal axis, and additional bearing means for supporting said second section from the first section and including a spherically curved surface on one or. said first and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movably engaging said spherically curved surface at a location offset vertically from the plane of said horizontal axes and at points on a sphere to support said second section while allowing said uni versal movement thereof, said one of the first and sec ond sections including a main body portion, a member adjustably mounted thereto and having said spherically curved surface formed thereon, and means for adjusting said member relative to said main body portion of the section.

12. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coactirig drive means on the table to rotatably drive said first section about an essentially vertical axis with the table, a second sec tion supported and driven by said first section and adapted to removably receive a kelly bushing, drive means on said second section for interfitting with said removable kelly bushing 'when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn and transmitting rotary motion between said sections, said universal connection including a third section, a first hinge connection mounting said third section to said first section f relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotaltmovement about a second essentially horizontal axis which intersects said first horizontal axis, and additional bearing means for sup porting said second section from the first section and including a spherically curved surface on one of said first and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movably engaging said spherically curved surface at a location offset vertically from the plane of said horizontal axes and at points on a sphere to support said second section while allowing said universal movement thereof, said one of the first and second sections including a main body portion, a member adjustably mounted thereto and having said spherically curved surface formed thereon, and a plurality of screws adapted to be tightened against and thereby adjust said member relative to said main body portion of the section.

13. A removable master bushing assembly for use in a well-drilling rotary table having an opening for passing well pipe vertically through the table, said assembly including a first section adapted to be received in said opening and removable upwardly therefrom, drive means on said first section movable into interfitting power transmitting engagement with coacting drive means on the table to rotatably drive said first section about an essentially vertical axis with the table, a second section supported and driven by said first section and adapted to removably receive a kelly bushing, drive means on said second section for interfittingtwith said removable kelly bushing when it is engaged with said second section to drive the kelly bushing therewith, a universal connection mounting said second section for universal movement relative to the first section as the table and sections turn and transmitting rotary motion between said section's, said universal connection including a third section, a first hinge connection mounting said third section to said first section for relative pivotal movement about an essentially horizontal axis, and a second hinge connection mounting said second section to the third section for relative pivotal movement about a second essentially horizontallaxis which intersects said first horizontal axis, and additional bearing means for supporting said second section from the first section and including a spherically curved surface on one of said first and second sections and means engaging the other of said first and second sections for transmitting vertical load forces thereto and movab-ly engaging said spherically curved surface at a location offset vertically from the plane of said horizontal axes and at points on a sphere to support said second section While allowing said universal movement thereof, said location at which said curved sun-face is engaged 'by said last mentioned means being spaced outwardly from said essentially vertical axis to allow extension of a well pipe through said assembly.

14. A rotary drilling unit for drilling holes in an earth formation under a body of water subject to wave action, the unit comprising a buoyant vessel floating in the water, a rotatable table disposed on the vessel and having a central opening through it, means for rotating the table with respect to the vessel about a substantially vertical axis, a master bushing disposed in the table opening, first means coupling the master bushing to the table so they rotate together, a substantially horizontal first gimbal ring disposed in the master bushing, second means coupling the first ring to the master bushing to force them to rotate together and to permit the first ring to pivot with respect to the master bushing about an axis through a diameter of the first ring, a substantially horizontal second gimbal ring disposed in the first ring, third means coupling the second ring to the first to force them to rotate together and to permit the second ring to pivot with respect to the first about an axis through the diameter of the second ring which is transverse to the said axis of the first ring, a bearing support having a first annular spherical surface carried by the rotary table to rotate with it, the second ring having a second annular spherical surface spaced from and concentric with the first surface, and an annular set of ball bearings disposed between and in contact with the two said surfaces to transmit downward thrust from the second ring to the rotary table independently of the said second and thind coupling means, the two annular spherical surfaces and set of bearings being disposed around the said axis about which the table is rotatable.

References Qited in the file of this patent UNITED STATES PATENTS Germany Oct. 21, 1935 

1. A BUSHING ASSEMBLY FOR USE IN A WELL-DRILLING ROTARY TABLE HAVING AN OPENING FOR PASSING WELL PIPE VERTICALLY THROUGH THE TABLE, SAID ASSEMBLY INCLUDING A FIRST SECTION HAVING A SPHERICALLY CURVED BEARING SURFACE AND ADAPTED TO BE RECEIVED IN SAID OPENING AND BE ROTATABLY DRIVEN BY THE ROTARY TABLE ABOUT AN ESSENTIALY VERTICAL AXIS, A SECOND SECTION SUPPORTED AND DRIVEN BY SAID FIRST SECTION AND HAVING A SPHERICALLY CURVED BEARING SURFACE AND ADAPTED TO ROTATIVELY DRIVE A KELLY, AND A UNIVERSAL CONNECTION MOUNTING SAID SECOND SECTION FOR UNIVERSAL MOVEMENT RELATIVE TO THE FIRST SECTION AS THE TABLE AND SECTIONS TURN, SAID UNIVERSAL CONNECTION INCLUDING A THIRD SECTION TURNING WITH SAID FIRST AND SECOND SECTIONS, A FIRST PIVOTAL CONNECTION BETWEEN SAID FIRST AND THIRD SECTIONS FOR DRIVING THE LATTER WITH THE FORMER WHILE ALLOWING RELA- 